RE: RFR(xs): 8210320: PPC64: Fix uninitialized variable in C1 LIR assembler code

4 Sep 2018


      Hi Gustavo , looks good  (not a reviewer however).
It  might not hurt to initialize   md and data   as well   in the same file  in emit_opTypeCheck  as well  ( even  without gcc complaints ) :


void LIR_Assembler::emit_opTypeCheck(LIR_OpTypeCheck* op) {
  LIR_Code code = op->code();
  if (code == lir_store_check) {
    Register value = op->object()->as_register();
    Register array = op->array()->as_register();
    Register k_RInfo = op->tmp1()->as_register();
    Register klass_RInfo = op->tmp2()->as_register();
    Register Rtmp1 = op->tmp3()->as_register();
    bool should_profile = op->should_profile();

    __ verify_oop(value);
    CodeStub* stub = op->stub();
    // Check if it needs to be profiled.
    ciMethodData* md;
    ciProfileData* data;
 ...


Best regards, Matthias
...
-----Original Message-----
From: ppc-aix-port-dev <ppc-aix-port-dev-bounces@openjdk.java.net> On
Behalf Of Gustavo Romero
Sent: Dienstag, 4. September 2018 15:42
To: hotspot-compiler-dev@openjdk.java.net
Cc: ppc-aix-port-dev@openjdk.java.net
Subject: RFR(xs): 8210320: PPC64: Fix uninitialized variable in C1 LIR assembler
code
Importance: High
Hi,
May I please request reviews for this tiny change that fixes two
uninitialized variables in PPC64 C1 LIR code?
Bug   : https://bugs.openjdk.java.net/browse/JDK-8210320
Webrev: http://cr.openjdk.java.net/~gromero/8210320/v1/
GCC 4.8 does not complain about these two uninitialized pointers ('data'
and 'md') but more recent versions, like 5.4.0 and 7.3.1, complain about
it:
In file included from
/home/gromero/hg/jdk/jdk/src/hotspot/share/c1/c1_Compilation.hpp:29:0,
                  from
/home/gromero/hg/jdk/jdk/src/hotspot/share/precompiled/precompiled.h
pp:286:
/home/gromero/hg/jdk/jdk/src/hotspot/share/ci/ciMethodData.hpp: In
member function ‘void
LIR_Assembler::emit_typecheck_helper(LIR_OpTypeCheck*, Label*, Label*,
Label*)’:
/home/gromero/hg/jdk/jdk/src/hotspot/share/ci/ciMethodData.hpp:595:10
0: warning: ‘data’ may be used uninitialized in this function [-Wmaybe-
uninitialized]
    int      byte_offset_of_slot(ciProfileData* data, ByteSize
slot_offset_in_data) { return in_bytes(offset_of_slot(data,
slot_offset_in_data)); }
                                                                                                     ^
/home/gromero/hg/jdk/jdk/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cp
p:2400:18: note: ‘data’ was declared here
    ciProfileData* data;
                   ^
/home/gromero/hg/jdk/jdk/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cp
p:2483:78: warning: ‘md’ may be used uninitialized in this function [-
Wmaybe-uninitialized]
      type_profile_helper(mdo, mdo_offset_bias, md, data, recv, Rtmp1,
success);
                                                                               ^
Thank you.
Best regards,
Gustavo

RE: RFR(xs): 8210320: PPC64: Fix uninitialized variable in C1 LIR assembler code

Baesken, Matthias